In previous arrangements for allowing hose and drogue refuelling from a tanker aircraft which is fitted with a refuelling boom, it has been possible to attach an adaptor to the boom, which has a hose and drogue attached thereto. Such an adaptor is known as a boom drogue adaptor. The adaptor provides fluid communication between the boom and the hose. However, the adaptor and hose/drogue can only be fitted when the aircraft is on the ground, such that the tanker aircraft must be configured either for boom refuelling or for hose and drogue refuelling during any particular flight.
In addition, in hose and drogue refuelling, upon engagement with the receiving aircraft, the hose develops slack as the receiver pushes the drogue towards the end of the hose which is attached to the boom, such that great care is required from the receiver aircraft to avoid excessive slack allowing the hose to whip in the air flow. This is frequently the cause of accidents.
In order to allow a change in configuration during flight, it has been proposed to mount a hose and drogue, attached to an adaptor, on the aircraft tail. Such an arrangement is shown in US 2006/0102791. A boom is provided which is movable during flight from a deployed position extending away from the aircraft where it can be used directly for refuelling, to a stowed position adjacent the aircraft in which it can be attached to the adaptor in the aircraft tail. In this position the hose and drogue communicates with the boom. The boom can then be extended away from the aircraft with the hose and drogue attached, which can be used for refuelling.
However this system has some shortcomings. Since the hose and drogue are mounted in the aircraft tail, the hose must be relatively short in order to provide sufficient ground clearance upon the aircraft taking off and landing. This leads to a lack of hose response such that high loads may be imparted to refuelling probes, and also to a smaller movement envelope for the receiver aircraft. Furthermore landings are made more difficult for the tanker aircraft because of the trailing hose. Also the problem of hose slack being created as the receiver makes contact is not addressed.
The present invention aims to address these problems.